The deleterious psychological, physical and social consequences of alcoholism are well documented. Thus an early identification of excessive alcohol consumption constitutes an important goal for society.
Present methods of diagnosis of excessive chronic alcohol consumption lack either specificity or sensitivity, or both. For example, fractures and general trauma from accidents which can aid in recognition of a hidden alcohol problem are not specific, since these can occur in many conditions and circumstances. In contrast, present laboratory tests such as the volume of red blood cells and the levels of certain serum enzymes have good specificity but are not sufficiently sensitive, since only a small fraction of individuals presenting for treatment of alcoholism have altered values in these tests: Skinner et al., Annals of Internal Med. 101: 847-851 (1984).
Acetaldehyde is a product of the metabolism of alcohol (ethanol) and is found in human blood after the ingestion of alcohol. Acetaldehyde is also known to bind covalently to proteins present in blood, both to plasma proteins and to proteins in red blood cells. Blood proteins are known to remain in the circulation for different periods of time, from days to weeks for plasma proteins and up to three months for red blood cell proteins.
Acetaldehyde levels in the blood of normal individuals are negligible, while blood levels of 20-100 .mu.M acetaldehyde are seen in alcoholics. Even at these latter levels, however, only a minor amount of acetaldehyde binds to proteins, so that detection of the acetaldehyde-bound proteins is not possible with previously available techniques.
For proteins which remain for a long time in the blood, a sensitive method for measuring the levels of acetaldehyde-protein condensates present can provide a cumulative record of the amount and time of acetaldehyde exposure and therefore of the relative amounts of alcohol consumed over a period of time. Such methods as are available at present to detect reliably low levels of acetaldehyde-protein condensates utilise reaction of the protein with highly radioactive acetaldehyde (Nguyen & Peterson, Proc. Soc. Exp. Biol. Med., 177, 226-233, 1984; Stevens et al., J. Clin. Invest. 67, 361-369, 1981; Israel et al., in `Aldehyde Adducts in Alcoholism`, p. 31, 1985.) These methods are expensive, difficult to implement with facility, require special precautions and are clearly not applicable to measuring acetaldehyde-protein condensates generated in vivo in humans.